This specification relates to engine harmonic enhancement.
In some situations, automobile operators find it desirable to hear the noise emanating from the engine of their automobile. For example, a driver of a sports car may want to hear engine noise as they accelerate. The operator may use the noise to determine when to shift gears or they may just find that engine noise enriches their driving experience.
However, many modern day automobiles are designed to reduce the amount of noise (e.g., road noise) that enters the automobile's cabin and reaches the operator. To achieve noise reduction, automobile designers often insulate the automobile's cabin with sound dampening materials (e.g., foam). The sound dampening materials do not discriminate between engine noise and other noise such as road noise. Therefore, the use of sound dampening materials tends to attenuate the amount of engine noise that reaches the operator. Furthermore, in some examples, the sound dampening materials attenuate certain frequencies of the engine noise more than others, resulting in an unnatural sounding engine noise reaching the operator.
Engine harmonic enhancement systems enhance the engine noise heard by the operator by playing a synthesized engine noise through the audio system in the cabin of the automobile.